Process for treating tobacco and similar organic materials

Abstract

In order to effect expansion of a shredded material, said material is impregnated with an inert organic liquid, which is subsequently vaporized. The major portion of the impregnation agent is removed by separation. In order to eliminate the residual amount of impregnation agent still contained in the material, the material is fed by conveyor belt (31) into a microwave chamber (35). The microwave chamber (35) is provided with microwave energy under continuous control conditions. The vapors are siphoned off and fed into a regenerator for recovery of the impregnation agent. Conditioned, pressurized air is directed at the material in the microwave chamber (35) through discharge nozzles (38) to cause the material to whirl up and become fluidized. The pressurized air serves as a carrier gas for the residual impregnation agent that is to be removed and may simultaneously be used for conditioning the tobacco.

What is claimed is: 
     
       1. A process for treating tobacco and similar organic materials comprising (a) impregnating the organic materials with an inert organic liquid and heating the impregnated materials above the boiling point of said inert organic liquid by contacting with a hot first gas under conditions which result in vaporization of the inert organic liquid and expansion of the organic materials,   (b) recovering a portion of the vaporized inert organic liquid and collecting expanded organic materials containing residual amounts of said inert organic liquid,   (c) subjecting the expanded organic materials to microwave radiation in a microwave chamber to vaporize the residual amounts of inert organic liquid contained in the expanded organic materials and   (d) introducing a second gas into contact with the expanded organic materials while the expanded organic materials are being subjected to said microwave radiation whereby the inert organic liquid is expelled from the expanded organic materials and is carried away by said second gas.   
     
     
       2. The process of claim 1 wherein the expanded organic materials containing residual amounts of said inert organic liquid are conveyed into the microwave chamber supported by a conveying surface and said second gas is discharged into the organic materials from beneath said conveying surface. 
     
     
       3. The process of claim 2 wherein the discharge pressure of said second gas is sufficient to cause fluidization of the organic materials. 
     
     
       4. The process of claim 1, 2 or 3 wherein the second gas is treated in a conditioning device to adjust its moisture content and/or its temperature before it is introduced into contact with the expanded organic materials. 
     
     
       5. Apparatus for treating tobacco and similar organic materials which previously have been impregnated with an inert organic liquid and heated above the boiling point of the inert organic liquid with a hot first gas to produce expanded organic materials containing residual amounts of inert organic liquid, said apparatus comprising (a) a microwave chamber having an inlet section, an outlet section and a central section located between and connected to said inlet and outlet sections,   (b) conveyor means arranged within said microwave chamber and having a conveying surface for supporting and transporting a layer of expanded organic materials containing residual amounts of inert organic liquid,   (c) means for directing microwave energy into the central section of the microwave chamber to vaporize the residual amounts of inert organic liquid contained in the expanded organic materials and   (d) nozzle means associated with said conveying surface in said central section of the microwave chamber for directing a second gas into contact with the organic materials as the organic materials are being subjected to microwave energy.   
     
     
       6. The apparatus of claim 5 wherein said conveyor means comprises a vibrating conveyor. 
     
     
       7. The apparatus of claim 5 wherein means are included for adjusting the moisture content and/or temperature of said second gas before it is directed into contact with the expanded organic materials. 
     
     
       8. The apparatus of claim 5, 6 or 7 wherein the conveying surface of said conveyor means substantially constitutes the floor of the microwave chamber and said conveying surface comprises a radiation shielding material. 
     
     
       9. The apparatus of claim 5 wherein the height of said microwave chamber above said conveying surface is significantly greater in the central section than in the inlet and outlet sections and said conveyor means extends substantially over the entire length of the inlet, central and outlet sections. 
     
     
       10. The apparatus of claim 9 wherein the conveying surface of said conveyor means substantially constitutes the floor of the microwave chamber and said conveying surface comprises a radiation shielding material.